The present invention relates generally to a trailer or dolly and relates particularly, though not exclusively, to a stowable trailer or dolly system.
Trailer or caravan axles are vulnerable to breakages, particularly under extended fatigue conditions which are experienced when a trailer or caravan is trailed large distances. When the axle breakage occurs in a remote location, which is often the case, the trailer or caravan must be abandoned and a tow truck taken to the trailer or caravan so that it can be trailed on its unbroken axle. Alternatively, for a single axle trailer or caravan, repairs to the broken axle must be made at the site of the breakage. In any event it is particularly inconvenient and expensive to repair the axle breakage.
Australian patent No. 521004 relates to a carry towing trailer known as a MOBITOW. The MOBITOW is essentially a dolly designed to be hitched to and drawn by a towing vehicle. The MOBITOW is configured to xe2x80x9cpiggybackxe2x80x9d the front or rear wheels of an immobilised motor vehicle. The MOBITOW includes a chassis which can be moved adjacent the ground and the front or rear wheels of the immobilised vehicle then drawn onto cradles provided on the chassis. The chassis is then raised to a trailerable position above the ground and the immobilised vehicle towed as required. Although the MOBITOW provides a relatively convenient means for towing a vehicle it still does not overcome the problems identified in the preceding paragraph.
An intention of the present invention is to provide a trailer or dolly which can be stowed beneath or within a vehicle chassis or sub-frame.
According to one aspect of the present invention there is provided a trailer or dolly comprising:
a chassis for carrying a load, said chassis adapted to be towed behind a vehicle or another trailer; and
a plurality of ground engaging wheels rotatably mounted to the chassis;
said chassis expandable to an operable configuration and contractible to a compact configuration, whereby in use, the trailer or dolly can be towed behind the vehicle or other trailer in a drawn position when the chassis is in the operable configuration, or the trailer or dolly can be stored beneath or within the vehicle or other trailer in a stored position when the chassis is in the compact configuration.
Preferably the chassis is adapted to be towed behind the vehicle or other trailer by a substantially horizontal articulated connection.
According to another aspect of the present invention there is provided a stowable trailer or dolly system comprising:
a chassis for carrying a load, said chassis adapted to be towed behind a vehicle or another trailer; and
a plurality of ground engaging wheels rotatably mounted to the chassis; and
means for locating the trailer or dolly chassis beneath or within the vehicle or other trailer, said means adapted to engage the chassis and move it into the stored position when the chassis is in the compact configuration,
said chassis expandable to an operable configuration and contractible to a compact configuration whereby in use, the trailer or dolly can be towed behind the vehicle or other trailer in a drawn position when the chassis is in the operable configuration, or the trailer or dolly can be stored beneath or within the vehicle or other trailer in a stored position when the chassis is in the compact configuration.
Typically, said means for locating the trailer or dolly chassis beneath or within the vehicle chassis or sub-frame includes a block and tackle arrangement coupled between the vehicle and the trailer or dolly chassis so as to permit lifting of the trailer or dolly into the stored position. More typically, the block and tackle arrangement comprises one or more blocks including a ratchet block together with a chain or rope designed to operatively cooperate therewith.
Alternatively, said means includes one or more rails movably coupled to the vehicle chassis or sub-frame, said rails designed to move adjacent the ground and thereafter engage the trailer or dolly chassis and/or the wheels so that the trailer or dolly can be raised into the stored position.
In yet another embodiment, said means include one or more hydraulic rams connected to the vehicle chassis or sub-frame and the trailer or dolly chassis, respectively, said rams being designed to raise and lower the trailer or dolly into the stored or trailed position.
Typically, the trailer or dolly chassis includes a pair of elongate transverse and longitudinal members interconnected so as to form a generally oblong or square shaped chassis frame. More typically, the pair of transverse and/or longitudinal members are of a telescopic construction so that said members in a retracted position allow the trailer or dolly to be accommodated beneath or within the vehicle chassis or sub-frame in the stored position.
Preferably, the trailer or dolly chassis also includes a central elongate member opposing ends thereof being connected between the pair of transverse members. More preferably, the central member is also of a telescopic construction so that extension and retraction of the central member can occur together with a corresponding movement in the pair of longitudinal members.
Preferably, the trailer or dolly farther comprises a draw bar connected to the trailer or dolly chassis, a towing hitch being mounted to an end of the draw bar so as to permit coupling of the trailer or dolly to a tow bar of the vehicle with the trailer or dolly in the drawn position.
Typically, the draw bar is telescopically coupled to the trailer or dolly chassis so that in an extended position the trailer or dolly can be hitched to the vehicle in the drawn position, and in a retracted position the trailer or dolly can be stowed beneath or within the vehicle chassis or sub-frame in the stored position.
Alternatively, the draw bar is detachably coupled to the trailer or dolly chassis so that with the draw bar detached from said chassis the trailer or dolly can be accommodated by the vehicle in the stored position.
Preferably, the wheels are each of a relatively small diameter wherein the trailer or dolly chassis can be located in the stored position with adequate clearance between said wheels and the ground. Generally, the diameter of the wheels is from between 200 to 500 mm.
Typically, the wheels are mounted to the trailer or dolly chassis via a stub-axle for each of said wheels. More typically, each of the stub-axles is retractably coupled to the trailer or dolly chassis so that the wheels car be located inwardly or outwardly of the chassis.
Typically, the stub-axles are connected to a solid or swivel stub-axle mount of the trailer or dolly chassis, the stub-axle mount being disposed relative to said chassis so as to provide adequate clearance between the ground engaging wheels and the ground with the trailer or dolly in the scored position. More typically, the trailer or dolly includes a suspension system, wherein the suspension system is in the form of wheels, tyres, stub-axles or stub-axle mounts which are adapted to absorb and/or cushion any ground impact forces.
Typically, the trailer or dolly chassis is designed to carry a front or rear portion of a carriage, the rear or front wheels, respectively, of the carriage being trailed along the ground. In this example the carriage may include a caravan having a broken or damaged front or rear axle.
Alternatively, the trailer or dolly chassis is constructed in the form of a box trailer having a tray mounted to the chassis frame, the tray being designed to carry the load.
In one embodiment, the trailer or dolly is constructed of an aluminium alloy being relatively lightweight.